1. Field of the Invention
The present general inventive concept relates to an inkjet image forming apparatus, and, more particularly, to an inkjet image forming apparatus having an array type print head.
2. Description of the Related Art
An image forming apparatus is an apparatus to print an image on a printing medium according to input image signals. Examples of the image forming apparatus include printers, copiers, facsimiles, and devices combining functions thereof.
Of various image forming apparatuses, an inkjet image forming apparatus is designed to print an image by ejecting fine droplets of ink onto desired positions on a printing medium. An inkjet image forming apparatus basically includes a print head having an ink discharge nozzle part, and a delivery device to deliver a printing medium.
The delivery device may adopt any one of various shapes of delivery members to deliver a printing medium. For example, the delivery device may deliver a printing medium by attaching the printing medium to a drum or belt, or by use of rollers arranged along a delivery path with a certain interval.
Using the rollers assures a simplified configuration and driving mechanism, and thus is advantageous to reduce the size of the inkjet image forming apparatus. However, such a roller delivery type setup may cause vibrations of a printing medium between rollers arranged downstream and upstream of a print head, thereby risking deterioration in print quality.
More specifically, if a printing medium vibrates in a printing zone where ink is discharged from a print head to a printing medium, a gap between the print head and the printing medium (head gap) varies, causing ink droplets to be ejected to unwanted positions on the printing medium, resulting in deterioration in print quality. In the worst case scenario, the print head may be brought into contact with, and contaminated by, a nozzle part of the print head.
Recently, there has been developed an inkjet image forming apparatus (hereinafter, referred to as an “array head type inkjet image forming apparatus”) to enable high-speed printing using an array type print head wherein a nozzle part has a length corresponding to a width of a printing medium.
In the array head type inkjet image forming apparatus, a print head does not move during printing, and an image is printed on a printing medium as the printing medium passes through a printing zone below the print head. However, the array head type inkjet image forming apparatus may suffer from serious deterioration in print quality due to vibration of a printing medium between rollers.